Method and system for supporting an evolved UTRAN

ABSTRACT

A method and system for supporting an evolved universal mobile telecommunication systems (UMTS) terrestrial radio access network (E-UTRAN) are disclosed. The system includes a wireless transmit/receive unit (WTRU), a UTRAN and an E-UTRAN. The UTRAN sends to the WTRU a list of available radio access technologies in a coverage area of the UTRAN. The list includes information related to the E-UTRAN. The WTRU receives the list and may initiate a handoff based on the list. The WTRU then sends its multi-mode/multi-RAT capability information including the E-UTRAN capability to the UTRAN. The UTRAN then sends a measurement capability message to the WTRU. The measurement capability message includes parameters necessary for performing measurements on an E-UTRAN channel. The WTRU performs measurements based on the measurement capability message and reports measurement results to the UTRAN. The UTRAN may initiate a handoff to the E-UTRAN based on the measurement results.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/700,799 filed Jul. 20, 2005, which is incorporated by reference as iffully set forth.

FIELD OF INVENTION

The present invention is related to wireless communication systems. Moreparticularly, the present invention is related to a method and systemfor supporting an evolved universal mobile telecommunication systems(UMTS) terrestrial radio access network (E-UTRAN).

BACKGROUND

Different types of wireless access systems have been developed toprovide different types of services and capabilities. Some examples ofwireless access systems include wireless local area networks (WLANs),(such as IEEE 802-based networks), and cellular networks, (such as UMTSterrestrial radio access network (UTRAN), a global system for mobilecommunication (GSM)/enhanced data rate for GSM evolution (EDGE) radioaccess network (GERAN), or the like). Each of these networks have beendeveloped and tailored to provide specific applications.

Proposals for an E-UTRAN (Long Term Evolution for UTRAN and evolvedNode-B (E-Node-B)) have been made to improve wireless system capacityand enhance performance. The E-UTRAN will provide significant advantagesover existing wireless communication systems and additional services maybe available through the higher bit rate and lower latency provided bythe E-UTRAN. FIG. 1 shows a conventional integrated wirelesscommunication system 100 including an E-UTRAN 114. The system 100includes an access system stratum 110, a network stratum 120 and amultimedia stratum 130. The access system stratum 110 includes aplurality of radio access networks (RANs) 111-115, a core network (CN)116 and an evolved CN 117. The RANs 111-115 include a generic accessnetwork (GAN) 111, a GERAN 112, a UTRAN 113, an E-UTRAN 114 and aninterworking wireless local area network (I-WLAN) 115. The RANs 111-115are connected to the CN 116 or the evolved CN 117 to provide services,(such as multimedia services from an Internet protocol (IP) multimediasubsystem (IMS) 131), to one or more WTRUs while interacting with anauthentication, authorization and accounting (AAA) server 121, a mobileIP (MIP) server 122, or other network entities in the network stratum120 via a gateway general packet radio services (GPRS) support node(GGSN) 118 or a packet data gateway (PDG) 119.

Currently, multimode wireless transmit/receive units (WTRUs) configuredto support multiple wireless communication systems are available. Thecapabilities of each of the WTRUs may vary. For example, some WTRUs maysupport only UMTS, while other WTRUs may support multiple mode ofoperations such as I-WLAN, GERAN, and/or E-UTRAN. The WTRUs that arecapable of supporting E-UTRAN will also be available in the future.

Therefore, it would be desirable to provide a method and system forsupporting an E-UTRAN such that the WTRUs may receive and utilize suchadditional E-UTRAN capabilities and services.

SUMMARY

The present invention is related to a method and system for supportingan E-UTRAN. The present invention extends conventional methods andprocedures for supporting multimode operations within UMTS-basedwireless communication system, (i.e., UTRAN), in order to support theaddition of the new technology, (i.e., E-UTRAN), to the system. Theconventional procedures are specified in third generation partnershipproject (3GPP) standards (e.g., TS25.331). The system, herein, includesa WTRU, a UTRAN and an E-UTRAN. A conventional UTRAN sends to the WTRU alist of available radio access technologies (RATs) in a coverage area ofthe UTRAN. The list includes information related to the existing RATattributes such as technology type, bit rate, bandwidth, or the like.The present invention introduces the information related to E-UTRAN tothis list. The WTRU receives this list during initial access or duringhandoff procedures. Upon receiving the list, an E-UTRAN capable WTRU mayconfigure/reconfigure the WTRU to receive E-UTRAN services based on thelist through handoff procedures or system reselection procedures. TheE-URAN capable WTRU may send its multi-mode/multi-RAT capabilityinformation including the E-UTRAN capability to the UTRAN during theinitial access, (i.e., attach procedures), or when requested by asystem. During a normal handoff procedure, the UTRAN sends a measurementcapability message to the WTRU. The measurement capability messageincludes parameters necessary for performing measurements on an E-UTRANchannel. The WTRU performs measurements based on the measurementcapability message and reports measurement results to the UTRAN. TheUTRAN may initiate a handoff to the E-UTRAN based on the measurementresults. In idle operation, the WTRU may decide to re-select to theE-UTRAN based on the capability information received earlier from theUTRAN. The WTRU uses this information to configure the transmitter andreceiver bandwidth, bit rate, frequency band, or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding of the invention may be had from thefollowing description of a preferred embodiment, given by way ofexample, and to be understood in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a diagram of a conventional wireless communication system;

FIG. 2 shows a wireless communication system configured in accordancewith the present invention; and

FIG. 3 is a flow diagram of a process for supporting E-UTRAN inaccordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

When referred to hereafter, the terminology “WTRU” includes but is notlimited to a user equipment, a mobile station, a fixed or mobilesubscriber unit, a pager, or any other type of device capable ofoperating in a wireless environment.

The features of the present invention may be incorporated into anintegrated circuit (IC) or be configured in a circuit comprising amultitude of interconnecting components.

FIG. 2 shows a wireless communication system 200 configured inaccordance with the present invention. The system 200 includes aplurality of RANs 210 a, 210 b, deployed under different RATs, and acore network 220 which may be an all Internet protocol (IP) network(AIPN). The core network 220 is connected to other networks, such as apublic switching telephone network (PSTN) 230, the Internet 240, or thelike. Each of the RANs 210 a, 210 b may be a GAN, a GERAN, a UTRAN, anE-UTRAN, an IEEE-based I-WLAN, or any type of wireless access network.

In order to optimize mobility among diverse RANs 210 a, 210 b, the corenetwork 220 provides open interfaces for mobility management (MM) 222that allow the operator of the core network 220 to direct WTRUs 250towards the most suitable RANs 210 a, 210 b. The core network 220 alsoprovides open interfaces that allow the WTRUs 250 to access other AIPNservices, such as session control (SC) 224, authentication,authorization and accounting (AAA) 226 and a policy control 228.

A WTRU 250 is a multi-mode WTRU equipped with at least two radio unitsconfigured to support communication with at least two different RATs.For example, the WTRU 250 may include one radio unit for communicatingwith an E-UTRAN and the other radio unit for communication with anI-WLAN. The WTRU 250 establishes a connection with one of the RANs andmay perform a handoff to a target RAN if handoff criteria is met by thetarget RAN.

A handoff may be initiated manually or automatically in the system 200.In the manual handoff process initiated by a user of the WTRU 250, theuser knows the existence of alternative RATs, (such as E-UTRAN), in itscurrent geographic location and switches between them, (e.g., betweenthe UTRAN and the E-UTRAN). The automatic handoff process may beinitiated by the WTRU 250, or by the RAN 210 a, 210 b or the corenetwork 220.

In the WTRU-initiated handoff, the WTRU 250 detects the existence ofalternative RATs, (such as an E-UTRAN), and initiates a handoff process,(e.g., to the E-UTRAN), based on the preference of the user of the WTRU250. The WTRU 250 receives necessary information, (such as handoffpolicies, resource status, or the like), from the network, (e.g., a RAN210 b or the core network 220). The WTRU 250 tracks the locations ofcoverage areas of the RANs 210 a, 210 b and initiates the handoffprocess based on predetermined handoff criteria.

In a system initiated handoff, the core network 220, (or the RAN 210 a,210 b), recognizes that the WTRU 250 is capable of supporting multipleRATs, (including E-UTRAN), and requests necessary information, (such aspower measurements), from the WTRU 250. The core network 220, (or theRAN 210 a, 210 b), tracks the location of the WTRU 250 and initiates thehandoff procedures based on a set of criteria, (such as the mobility ofthe WTRU 250, requested bandwidth, applications, load balancing,subscriber's profile, the measurement reports provided by the WTRU 250,or the like), once the WTRU 250 is within the coverage area of a targetRAN.

FIG. 3 is a flow diagram of a process for supporting an E-UTRAN inaccordance with the present invention. A WTRU 352 listens to a channel,(e.g., a broadcast control channel (BCCH)), on the UTRAN 354 (step 302).The UTRAN 354 sends, (or indicates), a list of available RATs, (such asE-UTRAN 356 RAT), within the coverage area of the UTRAN 354 to the WTRU352 (step 304). The list of available RATs is preferably sent via aUTRAN cell information list message. However, the list may be sent viaany type of messages.

The UTRAN cell information list message contains information onintra-frequency cells, inter-frequency cells and inter-RAT cells. Theconventional UTRAN cell information list message is modified to includenew information elements (IEs) for the E-UTRAN 356. The E-UTRAN 356 maybe based on orthogonal frequency division multiplexing (OFDM), or anyother type of air interface. In OFDM case, the UTRAN cell informationlist may include OFDM selection and reselection information, basetransceiver station identity code (BSIC), system specific measurementinformation, or the like. The system specific measurement informationenumerates supported frequencies, bandwidths, output power, or the like.Table 1 shows an exemplary UTRAN cell information list message includingnew IEs (shown in bold fonts) in accordance with the present invention.TABLE 1 Information Element/Group name Need Multi Type and referenceSemantics description Intra-frequency cell info OP 1 . . .<maxCellMeas> >CHOICE position MP status >>Occupied >>>Cell info MP Cellinfo 10.3.7.2 >>Vacant No data Inter-frequency cell info OP 1 . . .<maxCellMeas> >CHOICE position MP status >>Occupied >>>Frequency info MPFrequency info 10.3.6.36 >>>Cell info MP Cell info 10.3.7.2 >>Vacant Nodata Inter-RAT cell info list OP >Inter-RAT cell info OP 1 . . .<maxCellMeas> >>CHOICE position MP status >>>Occupied >>>>CHOICE RadioAccess Technology >>>>>GSM >>>>>>Cell selection MP Cell selection andre- and re-selection info selection info for SIB11/1210.3.2.4 >>>>>>BSIC MP BSIC 10.3.8.2 >>>>>>BCCH ARFCN MP Integer (0 . .. 1023) >>>>>IS-2000 >>>>>>System specific enumerated For IS-2000, usefields measurement info (frequency, timeslot, from TIA/EIA/IS-2000.5,colour code, output subclause 3. 7.3.3.2.27, power, PN offset) CandidateFrequency Neighbour List Message >>>>>OFDM >>>>>>OFDM MP selection andre- selection info >>>>>>BSIC MP >>>>>>System MP enumerated Specificmeasurement (frequency, info bandwidth, output power) >>>Inter-RAT cellinfo OP Integer (0 . . . 3) indicator >>Not present No data

Referring again to FIG. 3, the WTRU 352 receives the list and stores it(step 306). Based on preset user preference, the WTRU 352 sends itsmulti-mode/multi-RAT capability information to the UTRAN 354 (step 308).The multi-mode/multi-RAT capability information indicates a support ofE-UTRAN and/or other RATs. For example, the multi-mode/multi-RATcapability information may indicate a support of OFDM, a support ofE-UTRAN to UTRAN handoff, OFDM radio frequency (RF) capability, OFDMmeasurement capability, or the like. The support of OFDM may enumeratethe supported OFDM channel bandwidth, (e.g., 1.25 MHz, 2.5 MHz, 5 MHz,10 MHz, 15 MHz, 20 MHz). The support of E-UTRAN to UTRAN handoff ispreferably a Boolean value indicating such capability of the WTRU.

The OFDM RF capability and OFDM measurement capability indicate OFDM RFand measurement capabilities of the WTRU to the UTRAN. An OFDM channelmay have different bandwidth depending of system configuration and thedesired bit rate and delay associated with certain services. Forexample, in order to achieve the highest bit rate allowed, (e.g., 100Mbps), the E-UTRAN must transmit and receive using the highest bandwidthallowed, (e.g. 20 MHz). The E-UTRAN may run several combinations ofthese services (different bandwidths for different WTRUs). Therefore,the handoff to the E-UTRAN should be triggered based on the OFDM RFcapabilities of the WTRU. During handoff, when the WTRU performsmeasurements, the WTRU is preferably tuned and configured to a certainchannel frequency and a specific bandwidth for the measurements. Whenthe WTRU reports the measurements to the UTRAN, the UTRAN correlates themeasurements with the physical attributes of the E-UTRAN channels. Thisguarantees that the handoff is done accurately to the correct targetE-UTRAN channel that supports the desired bit rate and delayrequirements.

The multi-mode/multi-RAT capability information may be sent via aconventional UTRAN WTRU multi-mode/multi-RAT capability message, WTRUradio access capability message, WTRU radio access capability extensionmessage, or any other type of message. Tables 2-4 show an exemplaryUTRAN WTRU multi-mode/multi-RAT capability message, a WTRU radio accesscapability message and a WTRU radio access capability extension message,respectively, including new IEs (shown in bold fonts) in accordance withthe present invention. TABLE 2 Information Semantics Element/Group nameNeed Multi Type and Reference description Multi-RAT capability Supportof GSM MP Boolean Support of multi-carrier MP Boolean Multi-modecapability MP Enumerated (TDD, FDD, FDD/TDD) Support of UTRAN to CV-Boolean GERAN NACC not_iRAT_HoInfo Support OFDM MP Enumerated(1.25 M,2.5M, 5M, 10M, 15M, 20 MHz, or range) Support E-UTRAN to Boolean UTRANhandoffs

TABLE 3 Information Element/Group name Need Multi Type and referenceSemantics description Access stratum release MP Enumerated(R99)Indicates the release of indicator the UE. The IE also indicates therelease of the RRC transfer syntax supported by the UE . . . CV-Enumerated(REL-4, 13 spare values are not_rrc_connectionSetupCompleteREL-5 needed. REL-6) DL capability with OP Enumerated(32 kbps,simultaneous HS-DSCH 64 kbps, 128 kbps, configuration 384 kbps) PDCPcapability MP PDCP capability 10.3.3.24 RLC capability MP RLC capability10.3.3.34 Transport channel MP Transport channel capability capability10.3.3.40 RF capability FDD OP RF capability FDD 10.3.3.33 RF capabilityTDD OP RF capability TDD One “TDD RF capability” 10.3.3.33b entity shallbe included for every Chip rate capability supported. 1 to 2 RFcapability OFDM OP OFDM RF (E-UTRAN) capability x.x.x Physical channelMP Physical channel capability capability 10.3.3.25 UE multi-mode/multi-MP UE multi- RAT capability mode/multi-RAT capability 10.3.3.41 Securitycapability MP Security capability 10.3.3.37 UE positioning capability MPUE positioning capability 10.3.3.45 Measurement capability CH-Measurement fdd_req_sup capability 10.3.3.21

TABLE 4 Information Element/Group name Need Multi Type and referenceSemantics description Frequency band MP 1 to specific <maxFreqbandsFDD>capability list >Frequency MP Enumerated(Band I, One spare value isneeded band Band II, Band III, Band VI, Band IV, Band V, OFDMband) >Frequency OP Enumerated(Extension This IE indicates the supportedband 2 Indicator frequency bands beyond Band OFDM band) VIII (yet to bedefined) Fifteen spare values are needed >RF capability MD RF capabilityFDD the default values are the same FDD extension extension 10.3.3.33avalues as in the immediately preceding IE “RF capability FDD extension”;the first occurrence is MP >Measurement MP Measurement capabilitycapability extension extension 10.3.3.21a >RF capability MD RFcapability OFDM OFDM >Measurement MP Measurement capability capabilityOFDM OFDM

Referring again to FIG. 3, the UTRAN 354 receives the WTRUmulti-mode/multi-RAT capability message (step 310). The UTRAN 354 thensends a measurement capabilities message to the WTRU 352 (step 312). Themeasurement capability message defines the parameters necessary for themeasurements. New IEs for the E-UTRAN are included in the conventionalmeasurement capability message and the measurement capability extensionmessage for the E-UTRAN parameters, (e.g., OFDM measurement parametersfor each frequency bands). Each IE in the measurement capability messageand the measurement capability extension message is a Boolean valueindicating whether downlink or uplink compressed mode is required toperform measurements on each frequency band.

Tables 5 and 6 show an exemplary UTRAN measurement capability messageand a measurement capability extension message, respectively. The newIEs introduced in accordance with the present invention are shown inbold font. TABLE 5 Information Element/Group Type and name Need Multireference Semantics description Need for downlink compressed mode FDDmeasurements MP Boolean TRUE means that the UE requires DL compressedmode in order to perform measurements on FDD 3.84 Mcps TDD CV- BooleanTRUE means that the UE requires DL measurements 3.84_Mcps_tdd_supcompressed mode in order to perform measurements on 3.84 Mcps TDD 1.28Mcps TDD CV- Boolean TRUE means that the UE requires DL measurements1.28_Mcps_tdd_sup compressed mode in order to perform measurements on1.28 Mcps TDD GSM measurements CV- gsm_sup >GSM 900 MP Boolean TRUEmeans that the UE requires DL compressed mode in order to performmeasurements on GSM 900 >DCS 1800 MP Boolean TRUE means that the UErequires DL compressed mode in order to perform measurements on DCS1800 >GSM 1900 MP Boolean TRUE means that the UE requires DL compressedmode in order to perform measurements on GSM 1900 Multi-carrier CV-Boolean TRUE means that the UE requires DL measurement mc_sup compressedmode in order to perform measurements on multi-carrier OFDM E-UTRANmeasurements >1.25 MHz MP Boolean TRUE means that the UE requires DLcompressed mode in order to perform measurements on 1.25 MHz OFDM >2.5MHz MP Boolean TRUE means that the UE requires DL compressed mode inorder to perform measurements on 2.5 MHz OFDM >5 MHz MP Boolean TRUEmeans that the UE requires DL compressed mode in order to performmeasurements on 5 MHz OFDM >10 MHz MP Boolean TRUE means that the UErequires DL compressed mode in order to perform measurements on 10 MHzOFDM >15 MHz MP Boolean TRUE means that the UE requires DL compressedmode in order to perform measurements on 15 MHz OFDM >20 MHz MP BooleanTRUE means that the UE requires DL compressed mode in order to performmeasurements on 20 MHz OFDM Need for uplink compressed mode FDDmeasurements MP Boolean TRUE means that the UE requires UL compressedmode in order to perform measurements on FDD 3.84 Mcps TDD CV- BooleanTRUE means that the UE requires UL measurements 3.84_Mcps_tdd_supcompressed mode in order to perform measurements on 3.84 Mcps TDD 1.28Mcps TDD CV- Boolean TRUE means that the UE requires DL measurements1.28_Mcps_tdd_sup compressed mode in order to perform measurements on1.28 Mcps TDD GSM measurements CV- gsm_sup >GSM 900 MP Boolean TRUEmeans that the UE requires UL compressed mode in order to performmeasurements on GSM 900 >DCS 1800 MP Boolean TRUE means that the UErequires UL compressed mode in order to perform measurements on DCS1800 >GSM 1900 MP Boolean TRUE means that the UE requires UL compressedmode in order to perform measurements on GSM 1900 Multi-carrier CV-Boolean TRUE means that the UE requires UL measurement mc_sup compressedmode in order to perform measurements on multi-carrier OFDM E-UTRANmeasurements >1.25 MHz MP Boolean TRUE means that the UE requires ULcompressed mode in order to perform measurements on 1.25 MHz OFDM >2.5MHz MP Boolean TRUE means that the UE requires UL compressed mode inorder to perform measurements on 2.5 MHz OFDM >5 MHz MP Boolean TRUEmeans that the UE requires UL compressed mode in order to performmeasurements on 5 MHz OFDM >10 MHz MP Boolean TRUE means that the UErequires UL compressed mode in order to perform measurements on 10 MHzOFDM >15 MHz MP Boolean TRUE means that the UE requires UL compressedmode in order to perform measurements on 15 MHz OFDM >20 MHz MP BooleanTRUE means that the UE requires UL compressed mode in order to performmeasurements on 20 MHz OFDM

TABLE 6 Information Element/Group Type and name Need Multi referenceSemantics description FDD MP 1 to measurements <maxFreqBandsFDD> >FDD MDEnumerated(Band The default value is the same as indicated Frequencyband I, Band II, in the IE “Frequency band” included in the IE “UE radioaccess capability extension”. One spare value is needed Band III, BandVI, Band The default value is the same as R99, if IV, Band V) the IE“FDD Frequency band 2” below is not included. The default value is thesame as the IE “FDD Frequency band 2”, if the IE “FDD Frequency band 2”is included. >FDD MD Enumerated(Extension The default value is the sameas indicated Frequency band 2 Indicator) in the IE “Frequency band 2”included in the IE “UE radio access capability extension”., if the IE“FDD Frequency band” above is not included. The default value is thesame as the IE “FDD Frequency band”, if the IE “FDD Frequency band” isincluded. Fifteen spare values are needed >Need for DL MP Boolean TRUEmeans that the UE requires DL compressed compressed mode in order toperform mode measurements on the FDD frequency band indicated by the IE“FDD Frequency band” >Need for UL MP Boolean TRUE means that the UErequires UL compressed compressed mode in order to perform modemeasurements on the FDD frequency band indicated by the IE “FDDFrequency band” TDD CV- 1 to measurements tdd_sup <maxFreqBandsTDD> >TDDMP Enumerated(a, Frequency band b, c) >Need for DL MP Boolean TRUE meansthat the UE requires DL compressed compressed mode in order to performmode measurements on TDD frequency band indicated by the IE “TDDFrequency band” >Need for UL MP Boolean TRUE means that the UE requiresUL compressed compressed mode in order to perform mode measurements onTDD frequency band indicated by the IE “TDD Frequency band” GSM CV- 1 tomeasurements gsm_sup <maxFreqBandsGSM> >GSM MP Enumerated(GSM450, Ninespare values are needed. Frequency band GSM480, GSM850, GSM900P,GSM900E, GSM1800, GSM1900) >Need for DL MP Boolean TRUE means that theUE requires DL compressed compressed mode in order to perform modemeasurements on GSM frequency band indicated by the IE “GSM Frequencyband” >Need for UL MP Boolean TRUE means that the UE requires ULcompressed compressed mode in order to perform mode measurements on GSMfrequency band indicated by the IE “GSM Frequency band” Multi-carrierCV- measurement mc_sup >Need for DL MP Boolean TRUE means that the UErequires DL compressed compressed mode in order to perform modemeasurements on multi-carrier >Need for UL MP Boolean TRUE means thatthe UE requires UL compressed compressed mode in order to perform modemeasurements on multi-carrier OFDM E- UTRAN measurements >1.25 MHz MPEnumerated(x, band y, z) >Need for DL MP Boolean TRUE means that the UErequires DL compressed compressed mode in order to perform modemeasurements on 1.25 MHz OFDM >Need for UL MP Boolean TRUE means thatthe UE requires UL compressed compressed mode in order to perform modemeasurements on 1.25 MHz OFDM >>2.5 MHz MP Enumerated(x, band y,z) >Need for DL MP Boolean TRUE means that the UE requires DL compressedcompressed mode in order to perform mode measurements 2.5 MHz OFDM >Needfor UL MP Boolean TRUE means that the UE requires UL compressedcompressed mode in order to perform mode measurements on 2.5 MHzOFDM >>5 MHz MP Enumerated(x, band y, z) >Need for DL MP Boolean TRUEmeans that the UE requires DL compressed compressed mode in order toperform mode measurements 2.5 MHz OFDM >Need for UL MP Boolean TRUEmeans that the UE requires UL compressed compressed mode in order toperform mode measurements on 5 MHz OFDM >>10 MHz MP Enumerated(x, bandy, z) >Need for DL MP Boolean TRUE means that the UE requires DLcompressed compressed mode in order to perform mode measurements 10 MHzOFDM >Need for UL MP Boolean TRUE means that the UE requires ULcompressed compressed mode in order to perform mode measurements on 10MHz OFDM >>15 MHz MP Enumerated(x, band y, z) >Need for DL MP BooleanTRUE means that the UE requires DL compressed compressed mode in orderto perform mode measurements 15 MHz OFDM >Need for UL MP Boolean TRUEmeans that the UE requires UL compressed compressed mode in order toperform mode measurements on 15 MHz OFDM >>20 MHz VMP Enumerated(x, bandy, z) >Need for DL MP Boolean TRUE means that the UE requires DLcompressed compressed mode in order to perform mode measurements 20 MHzOFDM >Need for UL MP Boolean TRUE means that the UE requires ULcompressed compressed mode in order to perform mode measurements on 20MHz OFDM

Referring again to FIG. 3, the WTRU 352 receives the measurementcapabilities message. The WTRU 352 then performs measurements on theE-UTRAN signals 315 on E-UTRAN channels indicated in the measurementcapabilities message and reports measurement results to the UTRAN 354(step 314). The UTRAN 354 may initiate a handoff to the E-UTRAN 356based on the measurement reports.

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the preferred embodiments or in various combinations with orwithout other features and elements of the present invention.

1. In a wireless communication system including a wirelesstransmit/receive unit (WTRU), a universal mobile telecommunicationsystems (UMTS) terrestrial radio access network (UTRAN) and an evolvedUTRAN (E-UTRAN), a method for supporting the E-UTRAN, the methodcomprising: the WTRU listening to a UTRAN channel; the UTRAN sending alist of available radio access technologies (RATs) in a coverage area ofthe UTRAN via the UTRAN channel, the list including information relatedto the E-UTRAN; and the WTRU receiving the list, whereby the WTRUreceives E-UTRAN services based on the list.
 2. The method of claim 1wherein the list is sent via a broadcast control channel (BCCH).
 3. Themethod of claim 2 wherein the list is included in a cell informationlist message.
 4. The method of claim 1 wherein the list is sent via adedicated channel.
 5. The method of claim 1 wherein a RAT of the E-UTRANis orthogonal frequency division multiplexing (OFDM).
 6. The method ofclaim 5 wherein the E-UTRAN information includes at least one of OFDMselection and reselection information, base transceiver identity code(BSIC), and system specific measurement information.
 7. The method ofclaim 6 wherein the system specific measurement information enumeratesat least one of supported frequency, bandwidth, and output power.
 8. Themethod of claim 1 further comprising: the WTRU sending amulti-mode/multi-RAT capability of the WTRU to the UTRAN; and the UTRANreceiving the multi-mode/multi-RAT capability of the WTRU.
 9. The methodof claim 8 wherein the multi-mode/multi-RAT capability indicates anE-UTRAN capability of the WTRU.
 10. The method of claim 9 wherein theE-UTRAN capability includes an orthogonal frequency divisionmultiplexing (OFDM) capability.
 11. The method of claim 10 wherein themulti-mode/multi-RAT capability includes at least one of an indicationof OFDM support, an indication of a support of handoff between the UTRANand the E-UTRAN, OFDM radio frequency capability, and OFDM measurementcapability.
 12. The method of claim 11 wherein the indication of OFDMsupport enumerates supported frequencies and bandwidths.
 13. The methodof claim 8 wherein the multi-mode/multi-RAT capability is sent via atleast one of a WTRU multi-mode/multi-RAT capability message, a WTRUradio access capability message, and a WTRU radio access capabilityextension message.
 14. The method of claim 8 wherein amulti-mode/multi-RAT capability is sent during an attach procedure. 15.The method of claim 8 wherein the multi-mode/multi-RAT capability issent upon request by the UTRAN.
 16. The method of claim 8 furthercomprising: the UTRAN sending a measurement capability message to theWTRU, the measurement capability message including parameters necessaryfor performing measurements on an E-UTRAN channel; the WTRU performingmeasurements based on the measurement capability message; and the WTRUreporting measurement results to the UTRAN.
 17. The method of claim 16further comprising: the UTRAN initiating a handoff of the WTRU to theE-UTRAN based on the measurement results.
 18. The method of claim 16wherein the measurement capability message includes parameters fororthogonal frequency division multiplexing (OFDM) measurements.
 19. Themethod of claim 1 further comprising: the WTRU initiating a handoff fromthe UTRAN to the E-UTRAN based on the list.
 20. The method of claim 19wherein the handoff is triggered by a user of the WTRU.
 21. The methodof claim 19 wherein the handoff is triggered automatically.
 22. Awireless communication system supporting an evolved universal mobiletelecommunication systems (UMTS) terrestrial radio access network(E-UTRAN), the system comprising: an E-UTRAN; a UTRAN configured to senda list of available radio access technologies (RATs) in a coverage areaof the UTRAN, the list including information related to the E-UTRAN; anda wireless transmit/receive unit (WTRU) configured to receive the listand receive E-UTRAN services based on the list.
 23. The system of claim22 wherein the UTRAN sends the list via a broadcast control channel(BCCH).
 24. The system of claim 23 wherein the UTRAN includes the listin a cell information list message.
 25. The system of claim 22 whereinthe UTRAN sends the list via a dedicated channel.
 26. The system ofclaim 22 wherein a RAT of the E-UTRAN is orthogonal frequency divisionmultiplexing (OFDM).
 27. The system of claim 26 wherein the E-UTRANinformation includes at least one of OFDM selection and reselectioninformation, base transceiver identity code (BSIC), and system specificmeasurement information.
 28. The system of claim 27 wherein the systemspecific measurement information enumerates at least one of supportedfrequency, bandwidth, and output power.
 29. The system of claim 22wherein the WTRU is configured to send its multi-mode/multi-RATcapability to the UTRAN.
 30. The system of claim 29 wherein themulti-mode/multi-RAT capability includes E-UTRAN capability.
 31. Thesystem of claim 30 wherein the E-UTRAN capability includes an orthogonalfrequency division multiplexing (OFDM) capability.
 32. The system ofclaim 31 wherein the multi-mode/multi-RAT capability includes at leastone of an indication of OFDM support, an indication of a support ofhandoff between the UTRAN and the E-UTRAN, OFDM radio frequencycapability, and OFDM measurement capability.
 33. The system of claim 32wherein the indication of OFDM support enumerates supported frequenciesand bandwidths.
 34. The system of claim 29 wherein themulti-mode/multi-RAT capability is sent via at least one of a WTRUmulti-mode/multi-RAT capability message, a WTRU radio access capabilitymessage, and a WTRU radio access capability extension message.
 35. Thesystem of claim 29 wherein the multi-mode/multi-RAT capability is sentduring an attach procedure.
 36. The system of claim 29 wherein themulti-mode/multi-RAT capability is sent upon request by the UTRAN. 37.The system of claim 29 wherein the UTRAN is configured to send ameasurement capability message to the WTRU, the measurement capabilitymessage including parameters necessary to perform measurements on anE-UTRAN channel, and the WTRU is configured to perform measurementsbased on the measurement capability message and report measurementresults to the UTRAN.
 38. The system of claim 37 wherein the UTRAN isconfigured to initiate a handoff to the E-UTRAN based on the measurementresults.
 39. The system of claim 37 wherein the measurement capabilitymessage includes parameters for orthogonal frequency divisionmultiplexing (OFDM) measurements.
 40. The system of claim 22 wherein theWTRU is configured to initiate a handoff of the WTRU from the UTRAN tothe E-UTRAN based on the list.
 41. The system of claim 40 wherein thehandoff is triggered by a user of the WTRU.
 42. The system of claim 40wherein the handoff is triggered automatically.